EGFR and pulmonary fibrosis: In the patients who had preexisting pulmonary fibrosis, thoracic radiation prior to EGFR-TKIs treatment was not associated with the development of EGFR-TKIs induced ILD, however, there was a weak but statistically significant association between the development of EGFR-TKIs induced ILD and EGFR mutation status (p = 0.0498).